<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>类选择器</title>
    <style>
        .ibm{
            background-color: blue;
        }
        .qianfeng{
            color: red;
            background-color: yellow;
        }
    </style>
<!-- 两个类标签有同一属性的时候采用就近原则（顺序谁在后谁优先） -->
</head>
<body>
    <div>wct-1</div>
    <div class="ibm qianfeng">wct-2</div>
    <div class="ibm">wct-3</div>
    <div class="ibm">wct-4</div>
    <div>wct-5</div>
    <div>wct-6</div>
</body>
</html>